Novel plasticized compositions



United States Patent Ofi ice 3,Zl9,6l Patented Nov. 23, 1965 3,219,615NOVEL PLASTICIZED COMPOSETIONS Ray Phillips, Murray Hill, N ..l.,assignor to FMC Corporation, New York, N.Y., a corporation of DelawareNo Drawing. flriginal application Get. 18, 1961, Ser.

No. 145,989, now Patent No. 3,120,545, dated Feb. 4,

1964. Divided and this application Apr. 5, 1963, Ser.

1 Claim. (Cl. 260-304) This application is a division of my copendingapplication Serial No. 145,989, filed October 18, 1961, now Patent No.3,120,545.

This invention relates to novel plasticized compositions, and moreparticularly, it relates to poly(vinyl alcohol) plasticized withtris(tetrahydrofurfuryl) phosphate.

Poly(vinyl alcohol) polymers are useful products which have excellentproperties such as solvent resistance, tensile strength, tearresistance, and flexibility. These polymers are useful in thepreparation of many adhesives, binders and films. The property ofpoly(vinyl alcohol) polymers which leads to their greatest potentialutility is their water-solubility. In many applications in which waterresistance is not necessary, these polymers may be preferred since theycan be handled as aqueous solutions, thus eliminating the necessity fororganic solvents. Also, there are many applications in which awater-solu ble polymer is specifically required. For example, thesepolymers are particularly useful in the preparation of water-solublefilms, which can be used for packaging measured amounts of commercialproducts such as soap, detergent, bluing, bath salts, disinfectants,insecticidal compositions, etc. In this application, the packagecontaining the measured amount of product is dissolved in a specifiedquantity of water to make up a solution of desired concentration,without the contents of the package ever touching the users hands.However, this potential use for poly(vinyl alcohol) has not as yet beenfully realized, because no completely satisfactory plasticizer has beenfound.

Conventional plasticizers for poly(vinyl alcohol), such as glycerine,ethylene glycol and triethylene glycol, act as plasticizers through amechanism involving the fact that they are humectants. These compoundsabsorb and retain a controlled amount of water which acts as the actualplasticizer. However, when these plasticized polymers are used aspackaging films, they have the disadvantage of being affected by changesin humidity which result in changes in physical properties such astackiness, hardness, chemical resistance, etc. For example, these filmsbecome soft when subjected to high humidity conditions and tend torupture easily. Furthermore, these conventional plasticizers arenutrients which support fungus and mold growth on the surface of thefilm. Accord ingly, there is a need for a true plasticizer forpoly(vinyl alcohol) which is not a humectant.

It is an object of this invention to provide a true plasticizer forpoly(vinyl alcohol).

It is another object to provide a water-soluble plasticizer forpoly(vinyl alcohol) which is not affected by changes in temperature andhumidity.

It is another object to provide a plasticizer for poly- (vinyl alcohol)which is not a humectant.

These and other objects will become apparent from the followingdescription of this invention.

I have discovered a new compound, tris(tetrahydrofurfuryl) phosphate,which surprisingly, despite its complex structure, is soluble in water,and is an excellent plasticizer for poly(vinyl alcohol). This novelester has the unusual combination of properties of being completelycompatible with poly(vinyl alcohol) and being Water-soluble, while atthe same time, not being a hurried taut. Thus, it can be used for makingpoly(vinyl alcohol) packaging films which Will ultimately dissolve inwater, but which otherwise have relatively stable properties, even whensubjected to drastic changes in humidity and temperature. Moreover, thisester does not support fungus or mold growth.

Tris(tetrahydrofurfuryl) phosphate may be prepared by the reaction oftetrahydrofurfuryl alcohol with phosphorus oxychloride in the presenceof an acid acceptor, such as triethylamine. The reaction is suitablycarried out by mixing tetrahydrofurfuryl alcohol with trimethylamine inthe presence of a solvent such as benzene, and adding phosphorusoxychloride dropwise while maintaining the reaction at 40-50 C. bycooling. When the reaction is complete, the triethylamine hydrochlorideprecipitate is filtered off, and the solvent is removed from the productby stripping under reduced pressure.

Another method by which tris(tetrahydrofurfuryl) phosphate may beprepared in higher purity is carried out by reacting tetrahydrofurfurylalcohol with sodium metal to form the sodium alcoholate, and reactingthis intermediate with phosphorus oxychloride to yield the desiredproduct. The product may be recovered by treating the oil layer withsoda ash and stripping to remove the sol vent. The concentrated productis then filtered and distilled.

Poly(vinyl alcohol) polymers are prepared by the hydrolysis ofpoly(vinyl acetate). Therefore, these polymers may differ as to thedegree of hydrolysis and as to molecular weight. For most applications,the polymer should be about 50100% hydrolyzed and have a viscosity inthe range of about 465 centiposies, measured as a 4% aqueous solution at20 C. using the Hoeppler falling ball method. Poly(vinyl alcohol) isfully discussed by Smith in Vinyl Resins, Reinhold Plastics ApplicationsSeries,

Reinhold Publishing Corp. 8), New York.

Although the amount of plasticizer used with the poly- (vinyl alcohol)will depend on the properties desired, generally about 20-40 parts perhundred parts of polymer are preferred. The plasticizer is readilyblended with polytfvinyl alcohol) by adding the plasticizer to anaqueous solution of the polymer.

Tris(tetrahydrofurfuryl) phosphate is particularly useful as aplasticizer for poly(vinyl alcohol) packaging films. However, this estercan also be used as a plasticizer in the preparation of poly(vinylalcohol) adhesives, binders and molded plastics.Tris(tetrahydrofurfuryl) phosphate is also compatible with many otherresins and is useful in other applications, for example as a plasticizerin poly(vinyl acetate) cements, and in polystyrene and polyacrylic floorfinishes. This ester also has surface active properties which make ituseful as a leveling agent in various coating materials, and as ananti-foam agent. It is also useful as a coalescing agent for resindispersions such as poly(vinyl acetate) emulsion coatings.

The following examples, illustrating the preparation oftris(tetrahydrofurfuryl) phosphate and its use as a plasticizer for poly(vinyl alcohol), are presented Without any intention that the inventionbe limited thereto. All parts and percentages are by weight.

Example I Tris(tetrahydrofurfuryl) phosphate Was prepared as follows:Two hundred twenty parts of tetrahydrofurfuryl alcohol and 222 parts oftriethylamine, dissolved in 800 parts of benzene, were charged to areactor and 101 parts of phosphorus oxychloride, dissolved in 200 partsof benzene, were added dropwise over a 30-minute period, whilemaintaining the reaction temperature at 40 60 C. The reaction mixturewas stirred at this temperature for an additional 5-hour period. Thetriethylamine hydrochloride precipitate was filtered off, and the excesssolvent was stripped off by reducing the pressure to 20 millimeters ofmercury while warming. The procedure resulted in a yield of 208 parts oftris(tetrahydrofurfuryl) phosphate of approximately 91.6% purity.

Analysis.Theoretical, C, 51.4; H, 7.78; P, 8.85. Found, c, 49.3; H,8.07; P, 8.78.

Example 11 A film was cast as follows: One hundred parts of 88%hydrolyzed poly(vinyl alcohol) having a viscosity of 22 centipoises,measured as a 4% aqueous solution at 20 C., was dissolved in 900 partsof water by heating. To the resulting solution was added 20 parts oftris(tetrahydrofurfuryl) phosphate. The resin solution was cast as aS-mil film on a sheet of single strength glass and dried for one hour at70 C.

Additional films were cast using the above procedure except fordifferences in the amount and type of plasticizer. A film containing 40parts of tris(tetrahydrofurfuryl) phosphate per hundred parts ofpoly(vinyl alcohol) was prepared, as well as films containing 20 and 40parts of glycerine, a conventional plasticizer, in place of thetris(tetrahydrofurfuryl) phosphate. No differences between freshlyprepared films could be visually observed under the conditions of astandard laboratory atmosphere.

Example Ill The relative hardness of poly(vinyl alcohol) filmsplasticized with tris(tetrahydrofurfuryl) phosphate under varioushumidity conditions were evaluated as follows: Using the resin solutionsprepared in Example II, films having a thickness of 1-2 mils were castand dried as before. These films were subjected to various humidityconditions at a temperature of 73 F. for a period of 48 hours. The filmswere rated as to hardness using a rating of 1 for the hardest film,which was very brittle, and a rating of 10 for the softest film, whichwas very weak. The following data were obtained:

The films plasticized with tris(tetrahydrofurfuryl) phosphate weresofter at 0% and relative humidity than the brittle unplasticized films,while having improved hardness over the soft unplasticized film atrelative humidity. At 100% relative humidity the film plasticized withglycerine was even softer than the unplasticized film.

As will be apparent to those skilled in the art, numerous otherpoly(vinyl alcohol) polymers can be plasticized withtris(tetrahydrofurfury) phosphate to give similar results withoutdeparting from the spirit of the invention or the scope of the followingclaim.

I claim:

Poly(vinyl alcohol) plasticized with tris(tetrahydrofurfuryl) phosphate.

No references cited.

MORRIS LIEBMAN, Primary Examiner.

